Gas and air mixing device



Oct. 5, 1937. s. B. BROWN 2,094,978 I v GAS AND AIR MIXING DEVICE FiledNOV. 25, 1955 llllll/l/ 46 BY %m ATTORNEY.

Patented Oct. 5, 1937 UNITED STATEE eA'iENT. OFFICE GAS AND AIR MIXINGDEVICE Samuel Barton Brown, Los Angeles, Calif.

Application November 25, 1935, Serial No. 51,490

3 Claims.

This invention relates to improvements in gas and air mixing devices foruse in situations where gas and air are mixed in certain proportionspreparatory to combustion as, for example, in in- 'ternal combustionengines and in gas furnaces.

Among the objects of the invention are to providean improved means forinterspersing with each other a multiplicity of small streams of gas andair in such a manner as to mix the gas and air in a more intimatemanner; to provide improved means to keep dirt or dust from interieringwiththe efliciency with which the device operates; to provide a moreprecise means to regulate the proportions of air and gas admitted formixing; and to render the regulating devices more accessible and easy tooperate.

Speaking specifically, one valuable feature of the invention resides inthe provision of an improved arrangement of two cooperating sets of gassupply and air supply perforations, one of these sets being contained ina cylindrical piston, and the other in a cylindrical member with whichsaid piston is adjustably combined.

Other objects, advantages and features of the invention will hereinafterappear.

Referringto the accompanying drawing; which illustrates What is atpresent deemed to be a preferred embodiment of the invention,

Fig. 1 is a vertical mid-section of the complete device.

Fig. 2 is a partial transverse section taken on line 22 of Fig. 1.

Fig. 3 is a. developed vertical diagram illustrating in a conventionalmanner the arrangement and distribution of the gas supply apertures orforamina in and around the gas feeding tube.

Referring in detail to the drawing, the elongated structure shown isintended to be used in an upstanding position, the adjustable partsbeing contained within a cylindrical housing A having a body portion 5,a foraminated diametrically reduced portion or neck 6 below said body,and below said neck a lower end portion 1 which 415 is preferably of asomewhat greater diameter than said neck. Between the portions 6 and Ian outwardly projecting flange 8 is provided which is peripherallystepped at 9 in order to support an air distributing jacket Ill. Thehousing A both supports and protects the parts associated therewith.

Within the three-part housing which has been described is a cylindricalfloating piston B which has a head ll carried by a neck l2, said headhaving 1 workin f t within the body 5 of the housing. Near its lower endsaid neck has an external peripheral flange [3 which has a working fitwithin the neck 6 of the housing. Below the flange I3 said neck has athin skirt, the internal diameter of which is considerably greater thanthe internal diameter of the'neck l2.

Above the head ll of the floating piston there is contained within thehousing A an annular chamber l5 centrally of which is located theadjustable vapor supply tube 16. The upper end 10 portion of said tubeextends through and has a Working fit within a packing gland l1. Saidpacking gland is formed centrally upon a cap [8 which closes the top of'the said chamber l5 and is removably secured in place in any suitablemanner.

Air for thinning the fuel mixture is supplied through a tubularextension I9 of the jacket I0 which, by means of a pipe 20 communicateswith an air cleaner, not shown, which may be of any 20 approvedconventional type. Air is thus supplied to the annular chamber 2! withinsaid jacket. The housing body 5 and neck 6 combine to form the innerwall of said'chamber 2|. The foraminations 22 of the neck 6 freely admitthe 25 air to the space enclosed by said neck, but in operation air willnot circulate above the flange l3 of the float, there being a dead airspace 23 above said flange within the housing. Below said flange is theannular mixing chamber '23m.- 30

A plurality of open-ended tubes 24, one of which is shown in Fig. 1,extend through the head H and the lower flange l3 of the floatingpiston, air tight fits being made where said tubes pass through saidhead and flange. In operation 35 gaseous fuel is fed to the lowerportion of the housing A through a fitting Cwhich is secured to thelower end of the housing and has an intake port 25 into which is securedthe fuel supply pipe 26. This gas is conducted from said fitting upthrough the vapor supply tube IE to a portion of said tube which isprovided with a multiplicity of outlets or foraminations 21, saidoutlets being obstructable internally to the extent desired by means ofan adjustable shutter S, and are externally controlled by thelowerinside edge l3:c of the floating piston.

Suction from the manifold of an internal combustion engine, not shown,or other source, has 50 access to the housing A through the port 28 in'communication with which is shown a p p 29. This suction simultaneouslyentrains air throu h the foramina 22 of the housing and gas through theimmune 21 of the gas supply be I6, and

at the same time, through the tubes 24, creates suction in the upperchamber [5. The shutter S already mentioned, may be described as aslotted cylinder, or. tubular member open at its lower end and havingwide diametrically opposite slots 30; 301: out in its sides lie-- tweentheshutter plates 3|, 31cc. Each of said,

slots extends nearlyits entire length; The two 7 shutter side platesconstitute closure means and V are'slightly unequal in; width,-and-thesame is true as. to the width of the shutter 'slotsin order to controlmorev precisely the gas intake whilethe engine :is idlinggas willhereinafter be more," j

fully explained The top of said shutter'is closed, 'being furnished witha'central heado'r :enlargement 32. Abore extends through thishead and'Vwithin saidl bore is fixed a steel rod 33f by' means of a pin 32::fwhereby' saii'd shutter- 1's adjusted 1 v i; 1 irotationally withrespectto the gas supply tube t 2 0 16 within which it has a workingfit; A thin wzilleistefl tube. 34 is' sli-pped over jsaid rod 3'3andjextendsirom'the1ower'endiof the head 32 7 idownwardto a washeriss atits lower: enais d washer, in turnfrestin'gupon a packing'g'lan'di36zwhichiprevents leakage around: the rod '33;

1 1' Said t-ub'eiflalso takesrthe "thrust offa'stron'g j compressionspring which is 'coiled;aroun'd staid red -andtransfers itito the bottomfitting C. A"

thiust'=collar- 38f-at the top of said spring thrusts 1530 against around block '39 which-is soldered and f sweated into the upperend-offthe vapor supply ftubeflt and forms a :closurefor said tube; isa'id.thrust collaryi-sjprovidedjwitha packing gland 40 to prevent leakagearound the upperend 1301'- V tiatly stepped bearin'g block-3512 which,in "turn,

7 rests upon the topioithe "shutters. 7

' V i "DhCjVaPOIfSWPpIY'tubQ 'IB isT-held'against rotary port,presumably j :from an internal combustion engine, tends toiil-lft'saidpiston," Therefore; iifythe engine back -fires the pressure suddenly V Q2 eommunicatedto t the; interior "of: ithe housing V 7 would make thepiston; slam clownv violently on its valve seat if some-means were notprovided i to 'guard against this taking place; Hence a r release valve'fl is secured-to the capl8; :and is 7 normally' held closed byt-alightspring 4 4, per V mitting-the valve 'to be'i easilyp'pened byinside 7 pressure; The tension-of the spring "should be suchas'to'properlycontrol or x-nini-mize-themove- I ment of the'piston-B i-ncase 'o'f engine 'backfire.

1- :If -said' -springis too strong back-fire will slam V athe'pi'stondown; 'if,-the spring-is too weak the.

1 ,pistonwilLbe violently projected 'up'ag'ainst the 01151 justment ofthe rod '33 -together Y Rdtati E1 1 mm the'gshuter ;s fixed thereto isobtained by ineansofan arm 45 which is secured nearone end to the lower.endo'f said rod, Isaidlarm having ,anlupwardly offset portion j46"atits free "end [whichijs furnished withga set screw '41 engag'eable 7with"uie, outer .suriace .of V the tubular 'fitting c to maintain "saidarm in fthe'adjusted position. 'QBy preferenceandjas shown the arm-45 issecured [tojthevrod'by means of ascrew 48 which seats latthereby varyingthe vertical position. of the vapor supply tube 5 to expose more or lessof the lowestrow of perforations Zlbelow the lower end 7 tion ot therodhAt its 'lower' end' thei s'pring'35 jis' coiled around and 'r'ests upona circumferen- 1 erally in a recess provided therefor in the'rod; ""75Saidarm-45 'abuts'against the lower 6nd; o 3

l 2. v r 1 t 2 ,094,978 7 7 r H r 7 'f tting to limit the lifting actionof the spring 31 upon the rod conveyedthrough the collar 38 and block39and a split nut'49 which is secured V f Said nut 49 forms part of anauxiliary feed regulating means to regulate the feeding of minutequantities of gas to: an idling -engine. Said 10 nut 49 screws on to theupperend "of the rod 33 j ,7

and has a clamping screw 50 whereby said run: I may be clamped tosaidrod indifferent adjusted V positionswith regard to the length'of saidrods coi -the shutters. Owing to 'theffact that'the' block 39 is securedto the upper end portion of said tubegwhen said nut is adjustedupwardly20 it permits the-spring 3T torai'se said tubeto the extent? of suchwupward ad j'ustmentl when the opposition of the. spring. i

screwed down, the nut depresses the tube-against V V The g'as supplytube I6 is furnished with an 5' external integral collar 5! on which thefloating a 7 piston P'rests at t'helower limitof fits travel and V.

against which ithepiston -may 's't'rik'e wi-th *coni 1 lsiderableforce'in caseof engine back -firel-Q'Said 4 collar is beveled around itsupper elld 'to matc'hfiiill v the 'beveledrpartjl3m of the piston'i-n'order that these partsmay cooperate tojshut theig as' 6ft;completelywhen they are in contact'with ela'ch' other i v Theshockcreated by the piston}? in fallingfto F3 7 j its lowestpositionissuccessively transferred tfo'm said collar '51 to the tube '16, thenceto the block i 39 ingthe u per partof said*tube, and from said blocksuccessively to the collar '38-; spring -31g bearing block 351), Shutterheadf32fisteel tube :34, to

and finally *through the washer 35. to the-fitting C at the lower endofthe apparatus. l hespri'ng f 31, notwithstanding its sti'fl'ness absorbsa po'r-y tionof the shock; i 1 i e r A removable screw"plug 52 in thecap or cover i 18 "permits an opening to 'be made through said "cap forthe'injection of a fluid to cleanse the chamber [5 from 'the'products ofcombustion injected into said chamber by engine back-fire.

'In Fig. 3 is shown a developed schematic diato i amfiwhich" illustratesthe arrangement 61th? H p rforations 21 in the vap r gsupply :tube :16through which t fu l' gas emerges iromirsaid tube; J i w V i In-thisview the "gas holes 21am s own drilled on a spiral thread with avquadruple pitch and located in the first and third vertical quadrants jof the developed cylindrical gas tube l6, the

q ua'drants of which are progressively lettered fl q, 7 '2q, 3q and4'q,: and are located on alternate threads on'said quadruple pitch insuch a way that the 7 holes 21 open successively one after another at'an even progression whenthejfloating piston 13 rises, and closein'elike uniform manner during its fall. Since the air intakeholes 22are arranged on .a single pitch drilled at uniform distances apart theresult is that the ratio between the'gas and the'air hole areas remainsconstant at all the various vertical positions of the floating pistonVWhen the shutter is being turned so as to comrnencesopening thevertical rows of gas supply holes 21 it will not begin to open thesecond row 7 of holes 'iniil all the holes of the first rowhave beencompletely openedyand the second row to be opened is located inthe'quadrant opposite to that occupied by the first row opened.

As viewed in Fig. 2 the right hand segmental plate 313: of the shutter Sis slightly wider than the left plate 3| thereof, and the side opening36:: is slightly wider than the opening at the oppo site side of theshutter. Said shutter side plates are so arranged as to progressivelyopen vertical rows of the gas holes 21 as the shutter is rotationallyadjusted by turning the arm at the lower end of the device. It is owingto this'diiference in the widths of the side openings of the shutterthat only one row at a time of the holes 21 can be opened or closed. Theshutter may be so adjusted and set as to open or expose only a fractionof a row of holes for minute regulation of the gas flow. This shutteradjustment controls the gas-air ratio thus giving the mixture deliveredthe desired degree of fuel richness. The shutter may be turned to aposition wherein the side plates thereof completely cover the perforatedareas of the gas tube and thereby completely shut off the gas supply; orit may be turned to a position wherein its side plates come opposite tothe imperforate portions of the tube and uncover all its gas feedingholes or perforations.

The skirt M at the lower end of the floating piston B, is shown in fulllines in Fig. 1 at the upper part of its travel. In operation said skirtusually occupies a position wherein it compels all the air enteringthrough the holes 22 to be deflected downwardly before it mingles withthe gas coming out of the perforations 21. The skirt I4 keeps the dustand other foreign matter drawn in with the air from clogging the-slidingbearing between the tube l6 and said piston, and also keeps the dirt anddust from clogging the gas outlet perforations 21.

In the operation of the device as a fuel supply means for an internalcombustion engine the lever 45 at the base of the device shouldgenerally be set to maintain a four to eight inches water columnpressure beneath the floating piston B. After said lever has been set inthe proper position it is not usually necessary to vary the adjustment,which can be made permanent by screwing down the lever set screw 47.

The floating piston B automatically rises and falls according to thespeed and load of the engine. As said piston goes up it opens and as itgoes down it closes the gas and air holes in the same proportion, actingon the principle of a duplex multiple orifice meter.

When the engine is stopped, the weight of the piston B brings it down tothe shoulder afforded on the gas tube 16 by the collar 5! thereof, thusautomatically shutting off the gas to prevent it from entering theintake manifold and flooding the engine.

When the engine and magneto are in good condition the engine shouldstart with a quarter turn of the crank, or the striking of one impulseon the magneto.

The regulation of the nut 49 at the top of the device for feeding idlingengines has already been described.

During the operation of the device as a means for supplying fuel gas andair mixtures to the internal combustion engine of an automotive vehicle,when the operator desires to increase speed he opens more widely thethrottle (not shown) thus causing an increase in the quantity of fuelmixture withdrawn through the outlet 28 which leads to the manifold ofthe engine. This will cause the floating piston B to rise '(owingto thefact that the upper surface of the piston head I I is of a greater areathan the portion of the opposite end of the piston which is affected bythe suction) to a point where the pressure drop through the air holes 22is constant and equals theweight ofthe piston. Conversely a closingmovement of the tnrottie will lower the suction and cause less fuel tobe withdrawn, and allow the piston to descend till the device equalizesitself at a lower feed of fuel.

It is seen that the piston automatically controls the total port openingafforded by the air intake opening 22 and the fuel feed openings 2? insuch a manner as to maintain correct amounts of air and gas inproportion to the amount of mixture flowing out through the deliveryport 28 In practice it is found that the fuel used must be transmittedto the fuel feed conduit 26 in a more or less dry and vaporized form andnot in the form of liquid particles.

Owing to the fact that a constant air and gas ratio is automaticallyobtained over a full range of operation at different speeds, it ispossible to economize fuel and obtain maximum efficiency from givenquantities of fuel. It has been found that using the device inautomotive service results in a mileage increase of from ten totwentyfive percent for railway motor coaches, this saving being effectedby reason of the precise fuel feed adjustment obtainable in regard tothe required gas and air ratios.

I claim:

1. In a gas and air mixing device, a casing, a

vapor sup-ply tube mounted therein in av non-rotatable longitudinallyadjustable manner, said tube having foraminated fuel feeding areas, a

shutter having a working fit within said tube, a

turnable rod mounted axially within said tube, said tube having a blockfixed within one end portion thereof through which said rod turnablyprojects with a fluid tight fit, said shutter being fixed to said rodwithin said tube independently of said block, a spring coiled aroundsaid ro-d between said shutter and block and tending to move said rodlongitudinally away from said block, the opposite end portion of saidrod projecting through said casing and having its projecting portionfurnished with means to rotationally adjust the rod to vary the deliveryof vapor fuel through the aforementioned foraminated areas of said tube,an adjusting nut mounted upon the end portion of said rod which projectsbeyond said block, said nut cooperating with said spring to vary thelongitudinal position of said tube with relation to said shutter therebyto effect an auxiliary fuel feed adjustment, and'means to mingle airwith the regulated flow of gaseous fuel passing out from the foraminatedportion of said tube, said air mingling means including a floatingmember operable by engine suction to control fuel passages, and saidtube extending axially through said member with a. gas tight workingfit.

2. In a gas and air mixing device, ahousing, a gas supply tube mountedtherein and having outlet perforations, said housing having air inletperforations in a radially spaced relation to said gas outletperforations, there being an annular mixing chamber between theperforated portions of said tube and housing, a piston mountedexternally upon said tube with a working fit and having a working fitinternally of said housing, to control both the gas and air supply, saidpiston having a skirt portion consisting of a tubular shell spacedradially outward around said tube to ar- ,flect air entering theperforated portion of said housing towards an end portion of said mixingchamber-' asit minglesfwith the gas, said skirt be- 7 ing located belowsaid internal working fit of said piston, and conduit'meansto; ,conveythe mingled 'f gas and air from said mixing chamber, 1

'3. In a'gas and air mixing device, 'a casing, a

longitudinally adjustable vapor supply 5 tube g V vaporizing adjustmentbetween said shutter' and .mounted in said casing and having fuelfeeding f'openings, a shuttert'within said tub'e,ga'rod,-to which'saidshutteris fastened, said rod extending axiallyrthrough' said tube, saidtube-having a i5 closure fixed within :one end thereof through whichsaid 'rod' projects, a compression spring coiled around said rod andtendingto move said olosurelaway from said shuttenya tube to aid in itaking'thethrustof, said spring, one end of. said opposite endof saidtube, means externally en gaging'saidblosureto regulatexthe longitudinalposition of said tube in opposition to said spring thereby to cause arelative longitudinal :fueljmentioned fuel feeding openings of saidtube.

tube, and means to mingle airwith the regulated T n flow of gaseous fuelpassing out froni-theaforef v

